1. Field of the Invention
The present invention relates to a color thin-film EL display device having a plurality of display regions emitting light of different colors and adapted such that the display regions are selectively caused to emit light and a multicolored display is thereby made possible.
2. Description of the Prior Art
Recently, thin-film EL display devices are applied to displays for various apparatuses. General prior art color thin-film EL display devices are formed, as shown in FIG. 6, in a double insulation type six-layer structure, a structure in which a transparent conductive film 2, insulating film 3, EL light emitting layer 4, insulating film 5, and a counter electrode film 6 are piled up on a transparent glass substrate 1 one after another. The thin-film EL display device emits light by being applied with a.c. electric field of several tens Hz to several KHz between the transparent conductive film 2 and the counter electrode film 6 whereby active seed ions within the EL light emitting layer 4 are excited. In such a case, the EL light emitting layer 4 is constituted of a base material formed of ZnS, ZnSe, and the like and activators such as Cu, Cl, Mn, TbF.sub.3, SmF.sub.3, TmF.sub.3 added thereto, and the emitted colors can be changed by the kinds of the activators.
The conventional thin-film EL display devices have so far been more extensively used as surface light sources, and there have been made not so many studies on the thin-film EL display device which is capable of colored displaying by itself. As a device to make a colored display, the one as indicated in FIG. 7 is known, which is formed of thin-film EL display devices A, B, C, emitting light of different colors, piled up one after another, and respective patterns in the devices A, B, and C are adapted to be selectively caused to emit light to make the multicolored display.
In the above mentioned color display, however, since three devices A, B, and C must be used, their relative positions and so on made the structure complex. Also, since the light from the device disposed on the rearward side was visually sensed through the device disposed on the display surface side, there was such a demerit that the emitted colors are disturbed.